Diffraction light guide plate and method of manufacturing diffraction light guide plate

Abstract

A diffraction light guide plate, including: a first diffraction substrate; and a second diffraction substrate provided on the first diffraction substrate. The first diffraction substrate includes a first diffraction grating layer on one surface and a second diffraction grating layer on an opposite surface. The second diffraction substrate includes a third diffraction grating layer on one surface and a stress compensation layer on an opposite surface. The first diffraction grating layer separates light having a wavelength of 550 nm or more and 700 nm or less, the second diffraction grating layer separates light having a wavelength of 400 nm or more and 550 nm or less, the third diffraction grating layer separates light having a wavelength of 450 nm or more and 650 nm or less, and the stress compensation layer has stress in the same direction as a direction of stress of the third diffraction grating layer.

The invention claimed is: 
     
       1. A diffraction light guide plate, comprising:
 a first diffraction substrate; and 
 a second diffraction substrate provided on the first diffraction substrate, 
 wherein the first diffraction substrate includes a first diffraction grating layer in direct contact with one surface of the first diffraction substrate and a second diffraction grating layer in direct contact with an opposite surface of the first diffraction substrate, 
 wherein the second diffraction substrate includes a third diffraction grating layer in direct contact with one surface of the second diffraction substrate and a stress compensation layer in direct contact with an opposite surface of the second diffraction substrate, 
 wherein the first diffraction grating layer separates light having a wavelength of 550 nm or more and 700 nm or less, 
 wherein the second diffraction grating layer separates light having a wavelength of 400 nm or more and 550 nm or less, 
 wherein the third diffraction grating layer separates light having a wavelength of 450 nm or more and 650 nm or less, and 
 wherein the stress compensation layer has stress in a same direction as a direction of stress of the third diffraction grating layer. 
 
     
     
       2. The diffraction light guide plate of  claim 1 , wherein the stress compensation layer includes a reflection prevention pattern. 
     
     
       3. The diffraction light guide plate of  claim 1 , wherein a thickness of each of the first diffraction substrate and the second diffraction substrate is 0.1 mm or more and 2 mm or less. 
     
     
       4. The diffraction light guide plate of  claim 1 , wherein the first diffraction grating layer is spaced apart from the second diffraction substrate. 
     
     
       5. The diffraction light gyuide plate of  claim 1 , wherein each of the first, second and third diffraction grating layers includes:
 a first area, wherein light is incident on the first layer; 
 a second layer, wherein light is incident on the first area is expanded and moves in the second area; and 
 a third area, wherein light of the second area is extracted into the third area, 
 wherein the first area of each of the first, second and third diffraction grating layers are at corresponding positions of each of the first, second and third diffraction grating layers, respectively, and 
 wherein the third area of each of the first, second and third differaction grating layers are at corresponding positions of each of the first, second and third diffraction grating layers, respectively. 
 
     
     
       6. The diffraction light guide plate of  claim 5 , wherein a light refractive index of the third area of each of the first, second and third diffraction grating layers gradually increases from one side of the third area to an opposite side of the third area. 
     
     
       7. The diffraction light guide plate of  claim 5 , wherein the third area of each of the first, second and third diffraction grating layers includes a diffraction pattern including an inclined pattern structure, wherein a depth of the diffraction pattern gradually increases from one side of the inclined pattern structure to an opposite side of the inclined pattern structure. 
     
     
       8. The diffraction light guide plate of  claim 5 , wherein the third area of each of the first, second and third diffraction grating layers includes a diffraction pattern including a pattern structure, wherein a duty of the diffraction pattern gradually increases from one side of the pattern structure to an opposite side of the pattern structure. 
     
     
       9. A method of manufacturing the diffraction light guide plate of  claim 1 , the method comprising:
 preparing a first diffraction substrate; 
 preparing a second diffraction substrate; and 
 attaching the first diffraction substrate and the second diffraction substrate, 
 wherein the preparing of the first diffraction substrate includes forming a first diffraction grating layer in direct contact with one surface of the first diffraction substrate and forming a second diffraction grating layer in direct contact with an opposite surface of the first diffraction substrate, and 
 wherein the preparing of the second diffraction substrate includes forming a third diffraction grating layer in direct contact with one surface of the second diffraction substrate and forming a stress compensation layer in direct contact with an opposite surface of the second diffraction substrate. 
 
     
     
       10. The method of  claim 9 , wherein the preparing of the second diffraction substrate further includes forming a reflection prevention pattern on the stress compensation layer. 
     
     
       11. The method of  claim 10 , wherein each of the first, second and third diffraction grating layers and the stress compensation layer is formed using a photo-curable resin composition and an imprinting mold in an imprinting process. 
     
     
       12. The method of  claim 10 , wherein each of the first, second and third diffraction grating layers and the stress compensation layer is formed using a lithography process or a laser etch process. 
     
     
       13. The method of  claim 9 , wherein the attaching of the first diffraction substrate and the second diffraction substrate includes attaching the first diffraction substrate and the second diffraction substrate with a spacer therebetween so that the second diffraction grating layer of the first diffraction substrate is spaced apart from the second diffraction substrate.